Translate your survey into different languages. Click "Add translation" and choose the language that you want from the dropdown list. The view that opens up has the original text that you have entered on the left, and you can add the translated texts to the slows on the right. If you want to add multiple translations, finish the first translation and then follow the same steps to add another language. When you have added the languages, click the "auto-detect language..." selector and switch it on - this provides your respondents the possibility to choose from the translations that you have added.
If you need to send the questions out to be translated, or wish to work in a text format in order to create the translations - clicking the 3 dots in the top right hand corner allows you to export the translations in XLIFF file format. Once the translation is complete, you can import these in the same way.